stites / ffi-experimental

Code generation / FFI binding experiments using libtorch 1.0

Experimental Libtorch 1.0 FFI

Experimental work on next-gen ffi bindings into the c++ libtorch library in preparation for 0.0.2 which targets the 1.0 backend.

Approaches to explore:

• Use yaml specs (which seemed to have been cleaned up since PT ~ 0.4) instead of header parsing.
• Try inline-cpp functionality to bind the C++ API instead of the C API. Benchmark potential template haskell overhead vs. code generating C wrappers for C++ functions.
• Get a vertical slice working for a small number of functions.
• Scale up.

libtorch dependency retrieval and testing

libtorch-test/ and deps/ have scripts that retrieve libtorch and mkl-dnn library dependencies and builds/tests them using a minimal example.

To build:

cd libtorch-test
make

The makefile pulls in libtorch + mkl-dnn (not included in libtorch) prebuilt shared library files.

If the dependencies are retrieved and built successfully, you should see at the end of the build process the expected output of a random 2x2 matrix (exact values may differ):

...
[ 50%] Building CXX object CMakeFiles/libtorch-test.dir/cpptest.cpp.o
[100%] Linking CXX executable libtorch-test
[100%] Built target libtorch-test
export LD_LIBRARY_PATH=/Users/huanga13/projects-personal/ffi-experimental/libtorch-test/deps/mklml_mac_2019.0.1.20181227/lib:/Users/huanga13/projects-personal/ffi-experimental/libtorch-test/deps/libtorch/lib
source ./set-dyld-path.sh ; cd build ; ./libtorch-test
 0.5790  0.5507  0.6433
 0.9908  0.6380  0.3997
[ Variable[CPUFloatType]{2,3} ]

yaml -> binding codegen (WIP)

To run:

stack build codegen
stack exec codegen

To get CLI options:

stack exec codegen -- --help

ffi testing (WIP)

To run (currently works in the repl):

stack ghci --ghc-options='-fobject-code'  ffi
...
Prelude Main> main
Hello torch!
 0.2401  0.0901  0.9807
 0.9168  0.3757  0.4029
[ Variable[CPUFloatType]{2,3} ]
 1  1
 1  1
[ Variable[CPUFloatType]{2,2} ]
 0.1232  1.5721
 0.5392  0.2395
[ Variable[CPUFloatType]{2,2} ]
 1.1232  2.5721
 1.5392  1.2395
[ Variable[CPUFloatType]{2,2} ]
Prelude Main>

Contributions

Contributions/PRs are welcome.